JPH03174902A - Method and device for width-sizing hot slab - Google Patents

Abstract

PURPOSE:To improve sharply reduction while preventing the buckling of slab by making the distribution of width reduction of each set larger to the nearer set to the outlet side in the case that the width-sizing of slab is performed with a die which has at least two sets that consist of an inclined part and parallel part. CONSTITUTION:At least two sets which consist of the set of the inclined parts 41, 42 and parallel parts 43, 44 are provided as the shape of pressing surface of press die 40. Thus, press reduction is substantially dispersed in two times, the apparent buckling strength of the slab 1 is remarkably improved and the max. press reduction by one pass can be sharply improved. And, the max. width reduction can be increased by making the width reduction with the set, which is near the outlet side, of the inclined part 41 and parallel part 43 of the die 40 larger than the width reduction with the set, which is near the inlet side, of the inclined part 42 and parallel part 44 in the total width reduction of the slab 1 with the die 40.

Description

Detailed Description of the Invention (a) Industrial Application Field The present invention enables a drastic width change without buckling of the slab when the width of the slab to be subjected to rolling etc. is reduced by pressing from both end faces. The present invention relates to a hot slab width sizing method and apparatus which can be carried out.

(b) Conventional technology Reflecting the trend of diversification of industrial products in recent years.

The types and product sizes of steel sheets demanded by customers have become extremely diverse, and in particular, the product sizes required for steel sheets have increased significantly.

By the way, 1. Normally, in order to supply a steel plate of a desired size, a material suitable for that size is required. Most of the slabs that are used as the material are manufactured using the continuous casting method, so the more different steel sheet sizes that are required, the more it becomes necessary to own a large number of molds to obtain sloughs with dimensions that match them. However, there were major disadvantages in terms of mold manufacturing costs and storage. Moreover, casting slabs of various sizes led to the need to frequently replace the mold, which undermined the advantages of continuous casting, which was aimed at improving productivity.

For this reason, recently, a method of casting a slab of a constant width without changing the mold and changing the width by pressing the obtained slab from the width end face (hereinafter referred to as "width sizing") has been developed. It has become common practice to manufacture slabs of various widths.

As shown in FIG. 2 as a plan view, the above-mentioned "width sizing of a slab by pressing" is performed by changing the width end face of the slab 1 that moves continuously or intermittently to a slope 2. This is a means of compressing and sizing the slab in the width direction by rolling it down with a pair of pressing dies 4 having a pressing surface with a parallel part 5 on the exit side. Because the contact length between the mold and the mold is large,
Significant dogbone (bulging deformation in the thickness direction at the width end)
Since large reductions can be made without causing any problems, slabs of various sizes can be produced relatively easily.

In this case, the angle θ (FIG. 2) of the inclined part of the mold is usually selected in the range of 10 to 17 degrees. When θ is less than 10 degrees, the contact length with the slab mold during the same slab reduction becomes large, and the press load increases.

Therefore, the press equipment becomes larger and the equipment cost increases significantly. On the other hand, if θ exceeds 17 degrees, a situation will occur in which the slab is pushed out of the die when the tip of the slab is pressed (in the direction opposite to the slab advancing direction 11 in Fig. 2), and normal pressing cannot be performed. .

However, on the other hand, it has been pointed out that the method of sizing the slab width by pressing causes the troublesome problem of buckling of the slab 1 as shown in FIG. 5 when a large reduction is performed.

If buckling occurred in the slab as shown in Figure 6, not only would it be impossible to manufacture a slab of the specified width, but if the degree of buckling was large, it could even become impossible to feed into the subsequent horizontal rolling mill. .

Furthermore, in recent years, technological development has been underway to reduce the thickness of continuous casting slabs with the aim of simplifying the hot rolling process (reducing the number of stands, reducing the required rolling power, etc.). In this case, since the amount of width reduction at which buckling occurs becomes extremely small, a problem arises in that the single width sizing ability becomes extremely small.

Therefore, as a means to prevent the buckling.

As shown in FIG. 4, when reducing the width by pressing down the width end face of the slab 1 with a pair of pressing dies 4, the central part of the slab 1 is pressed from above and below with a holding tool 5 to prevent buckling. A method for preventing this has been proposed (Japanese Patent Laid-Open No. 53-22818).

However, with this method, it is not possible to expect a significant increase in the amount of width reduction, and it cannot be used as a method for fundamentally improving width sizing ability.

←→ Problems to be Solved by the Invention The problems to be solved by the present invention are to provide a method and a device for realizing a large reduction while preventing the buckling of the slab that conventionally occurs during width sizing. It is in.

B) Means for Solving the Problems The hot slab width sizing method of the present invention measures the width end face of a hot slab using a pair of pressing dies having a pressing surface consisting of an inclined part and a parallel part following this. Learn how to change the width of a slab by rolling it down sequentially.

At least two sets of an inclined part and a parallel part of the pressing die are provided, and of the total width reduction of the slab by the die, an amount of width reduction due to one set of inclined part and parallel part near the exit side of the die. The above-mentioned problem is solved by means of setting the width reduction amount to be larger than the width reduction amount due to a pair of inclined portions and parallel portions closer to the entry side.

The hot slab width sizing device of the present invention changes the width of the hot slab by sequentially pressing down the width end face of the hot slab using a pair of pressing dies having a pressing surface consisting of an inclined part and a parallel part following the pressing die. In the device that does.

The above problem is solved by providing at least two sets of inclined parts and parallel parts of the pressing die.

Preferably, the device of the present invention further includes press rollers at positions corresponding to the inclined portions.

(E) Effect Buckling that occurs during width sizing by pressing tends to occur more easily as the slab width becomes wider and as the width reduction amount increases. Furthermore, the buckling phenomenon does not occur gradually, but rather occurs suddenly when a certain amount of reduction is exceeded, as shown in FIG. Therefore, in order to suppress the occurrence of buckling and achieve a large width reduction, it is necessary to divide the width reduction into several times, rather than performing wide width reduction every time, to prevent the occurrence of buckling and reduce the total width. It is better to use a method that increases the amount of reduction. At that time 1
Regarding the distribution of the width reduction amount, it is better to increase the width reduction amount in the latter stage. because.

Comparison of the total possible width reduction amount of the rear stage when the width reduction amount of the front stage is increased and the total amount of width reduction possible of the rear stage when the width reduction amount of the front stage is decreased.

This is because the peak of the total width reduction amount is between the light width reduction in the first stage and the large width reduction in the second stage (see FIG. 6).

As mentioned above, the main factor that inhibits wide width reduction is the occurrence of buckling. Therefore, in order to perform a large reduction so that buckling does not occur, it is sufficient to carry out one width reduction in multiple steps.

The simplest method is the so-called lever press method, in which 51 presses are used to press the entire length of the slough and then press it again. However, this method significantly reduces efficiency, causes a drop in the temperature of the slab, and also requires a considerable length of the roller table before and after the press device, so it is not a practical solution.

Another possible method is to install two presses adjacent to each other and perform two presses in one bus. However, this method requires two presses.

Moreover, when each pair of molds is pressed, the other pair of molds must be separated from the slab, which makes the press structure extremely complicated and increases equipment costs. If the synchronization of the two pairs of dies is insufficient, the longitudinal compressive force and tensile force will act in a complex manner on the slab between the two pairs of dies, and this will not only cause the width of the slab to fluctuate after pressing, but also cause the slab to There is also the problem of buckling in the longitudinal direction.

In the present invention, as a means to solve the above-mentioned problems, the shape of the pressing surface of the mold is changed to at least two sets (as necessary) consisting of an inclined part and a parallel part.

There may be 5 or more pairs. ), the actual press reduction is distributed over two times (five times or more if necessary),
This makes it possible to significantly improve the apparent buckling strength of the slab and to significantly increase the maximum press reduction in one bath.

FIG. 6 shows the buckling occurrence situation in the above case. The figure shows the occurrence of buckling during width sizing of the slab when changing the combination of the width reduction amount of each group on the entry side and exit side using a slab with a width of 1600w x thickness of 200m x length of 9m. This is what I did. From the figure, it is clear that the maximum width reduction amount can be increased by increasing the width reduction amount closer to the exit side.

In other words, when sizing the width of a slab using a mold that has at least two sets consisting of an inclined part and a parallel part, the width reduction amount in each set is increased to the set closer to the exit side. This makes it possible to significantly improve the apparent buckling strength of the material and the maximum press reduction amount in one bath.

Also in this case, it is preferable to install one set of upper and lower restraining rollers on each set of inclined portions.

(e) Embodiment An embodiment of the hot slab width sizing apparatus of the present invention will be described with reference to FIG.

The width sizing device of the present invention sequentially presses down the width end face of a hot slab 1 using a pair of pressing dies 40 having a pressing surface consisting of inclined parts 41 and 42 and parallel parts 43 and 44. Change the width of

The apparatus for carrying out the method of the invention is provided with at least two sets of inclined parts 41.42 and parallel parts 43.44 of the pressing die 40. Furthermore, it is preferable to provide presser rollers 50 at positions corresponding to the inclined portions 41 and 42, respectively.

Further, as a result of various studies regarding the installation position of the presser roller 50, it has been found that it is effective to set X, , Xt in FIG. 1 within 300 m. That is, if X, , X, exceeds 300 degrees in FIG. 1, the effect of the presser roller decreases and buckling occurs in the slab.

Specific Example 1> In a press width sizing device using the mold shown in FIG. 1, the main dimensions are set as follows.

θ1=θ, = 15° L, = 400 mm L, = 6
00++m L, =800eamL, = 5
A slab of 60 mm width 1600 mm x thickness 270 mm x 9 m length is 1
Press width reduction amount in pass 600w (40w in inclined part 42
0mm reduction, 200 degrees reduction at the inclined part 41).

In this case, the position of the anti-buckling roller 50 is X, =
X, = 200 mm. When this anti-buckling roller 50 is not used, the amount of press reduction in one pass is 50
0+m (300 mm reduction at the inclined part 42, 20 m at the inclined part 41
0 mm reduction) was the maximum, and when this was exceeded, buckling occurred in the slab.

On the other hand, as a comparative example, when the same slab as above was rolled down in width using a normal mold shown in FIG. Width reduction was not possible due to slab buckling. That is, the method of the present invention enables a width reduction amount 1.5 times that of the conventional method.

Specific Example 2〉 A slab with a width of 1600 fl x a thickness of 200 sam x a length of 9 m was pressed in one pass with a press reduction amount of 450 m (160 m at the inclined part 42).
5H reduction, 285m reduction at the inclined part 41).

In this case, the position of the anti-buckling roller 50 is X, =
X, = 200ffi11. When this anti-buckling roller 50 is not used, the press reduction amount in one pass is 400so* (100so* at the inclined part 42,
1 and 220W reduction) was the maximum, and when this was exceeded, buckling occurred in the slab.

On the other hand, as a comparative example, when the same slab as above was rolled down in width using the normal mold shown in FIG. width reduction was not possible due to slab buckling. Namely.

By the method of the present invention, it is possible to achieve a width reduction of 40 factors compared to the conventional method.

<Effects of the Invention> According to the present invention, it is possible to improve the width sizing ability by a wide range regardless of the slab thickness, it is possible to greatly improve the efficiency of the continuous casting process, and it is also possible to improve product manufacturing in the hot rolling process. Industrially effective effects are brought about, such as easier division (schedule-free).

[Brief explanation of drawings]

FIG. 1 is a plan view of the hot slab width sizing apparatus of the present invention. FIG. 2 is a plan view of a conventional device. FIG. 6 is a side view showing the state of slab buckling that occurs during width sizing using a conventional device. FIG. 4 is a front view of the buckling prevention means of the conventional device. FIG. 5 is a graph showing the relationship between width reduction amount and buckling occurrence. FIG. 6 shows the limits of buckling when using the method of the present invention: Hot slab 40: Pressing die 41, 42: Inclined portion 43, 44: Parallel portion 50: Pressing roller.

Claims (1)

[Claims] 1. A method of changing the width of a hot slab by successively rolling down the width end face of the hot slab using a pair of pressing dies having a pressing surface consisting of an inclined part and a parallel part following the pressing die, At least two sets of an inclined part and a parallel part of the pressing die are provided, and of the total width reduction of the slab by the die, an amount of width reduction due to one set of inclined part and parallel part near the exit side of the die. A method for sizing the width of a hot slab, characterized in that the width reduction amount is set to be larger than the amount of width reduction due to a pair of inclined portions and parallel portions closer to the entry side. 2. In an apparatus for changing the width of a hot slab by successively rolling down the width end faces of a hot slab using a pair of pressing dies having a pressing surface consisting of an inclined part and a parallel part following the pressing dies, the slope of the pressing dies A width sizing device for a hot slab, characterized in that at least two sets of a section and a parallel section are provided. 3. The device according to claim 2, further comprising press rollers provided at positions corresponding to the inclined portions.